Incorrect value in calculating SPI by MDM.
Hello, I have a question. I am working with MDM software for calculate SPI, but I got a problem when I try calculate monthly drought, sometimes I got the values is 1.00e+300. how can i solve this proplem?. thank you so much.
MDM, DMAP and RDIT tool calculate SPI by using Gamma distribution. Sometimes during the calculation, the values change to NaN (1.00e+300) and we have a value in this month(or year).
Please check the month for dry or wet and if the month was dry change the value to -4 and if the month was wet change it to +4. If the month has a big value of rainfall so the month is wet and if the month has a low value of rainfall so it is a dry month.
Name: Ngoc Nguyen